DJI Fly only one thousand recordings allowed, ending at DJI_0999.MP4 (SOLVED)

[raulmavic]

Hi,

Reviewing my last flight I noticed last tree MP4 recordings missing at SD Card, but they are playable at DJI Fly Gallery.

Really curious is last recording at SD card is named DJI_0999.MP4

I found missing files at SD card into DJI cache folder named:
2020_08_10_07_52_36_Cache.mp4,
2020_08_10_07_52_50_Cache.mp4,
2020_08_10_07_53_00_Cache.mp4

Unfortunatelly, cache files are low quality and can't replace SD missing files.

Is this a DJI Fly bug ? Only one thousand recordings allowed ?

R.

 

[Deleted member 103366]

At or beyond DJI_0999.xyz, 999+1 becomes either 0000 or 0001 in a new folder on the mSD card, the new folder is likely to be named 101MEDIA,. The old folder, which is still on the mSD card would, in this instance, have been 100MEDIA.
This behaviour is common to most digital cameras be they phones, DSLR's or point and shoots. Put the card in a reader attached to a computer and have a look in the DCIM folder on the card, you should see '100'MEDIA and '101'MEDIA there

 

[raulmavic]

Good point, maybe I didn`t notice that 101MEDIA folder

Unfortunatelly I erased Mavic Mini SD card after copying files to my desktop computer.

I'll give a try some file recovering utility.

Thanks a lot !

R.

 

[Deleted member 103366]

Try ZarX Data Recovery Software, Solutions, Tutorials - ZAR Data Recovery it's slow but good, I dont't think it can recover files that have been written over but 'erased' stuff or formatting is not a problem for it.
Depending on how many images you 'lost' and whether or not the Metadata is preserved it might be worth sorting the recovered images by one of the date categories and then renaming the images via something like "Bulk Rename Utility"

 

[THE CYBORG]

THIS thread may help

 

[Deleted member 103366]

It's worth remembering that erasing or formatting a card does virtually nothing to remove images from a card.
I have bought quite a few 2nd hand CF cards, some from pro photographers. In the course of checking them I routinely ran ZarX on them, not to snope, but because it has an interface like the old Windows 98 defragmenter and shows a sector by sector map which happens to show any bad sectors it encounters.
You'd be amazed at how much it recovered form those cards, probably several 100 Mb's worth. I actually kept some of the images as they show 'techniques' in use.
I don't imagine many people are going to consider 'small capacity' mSD cards worth selling but if you are and you want to make sure your photos are gone, at least as far as casual recovery efforts are concerned, then you need to overwrite the images. The second piece of testing software that I use, H2testW, does this in the course of its checking.

 

[BadWolf1]

In the thread @THE CYBORG referred to I explained the standard - which has file names with 4 letters and 4 digits, allowing up to 9999 DJI appears to stop at 999 and start a new directory. That's not the usual way, but the standard doesn't say you can't do it.

It's worth remembering that erasing or formatting a card does virtually nothing to remove images from a card.

The difference between a full format and a quick format. A quick format on FAT just writes a new root directory. If you can find a non root directory it will have the file names and the starting block for each making recovery quite easy. Deleting a file also marks it as deleted without overwriting the bytes until something else needs them.

 

[Deleted member 103366]

Ta, what does a full format do?
How do you find " a non root directory " ?

 

[THE CYBORG]

A format simply makes it look like a drive is empty, no files show so you can write over anything that was on it.
Not a good explanation but can’t think of a better way to word it.

 

[Deleted member 103366]

But Badwolf1's post says theres a difference between quick and full formats, I know the latter take a LOT longer than the former but I am now curious about what the latter are doing during this extra time. Is it, for instance, writing random 0's and 1's to the storage media where previously organised data wxisted?
The way I think of it is as if the files are books in a library but the library is not laid out to a plan and books are stored anywhere (the analogy is, I believe, not true but it serves for the purpose of explanation) but the "where" is kept in and index. A format (quick?) wipes that index so the books are effectively lost unless you search book by book or location by location and the space they occupy is regarded as available to store new books.
However I take from Badwolf1's post that a full format does something else or more than wiping ' my index'

 

[BadWolf1]

Ta, what does a full format do?
How do you find " a non root directory " ?

When I really knew about this we were just moving to FAT16: NTFS , unix and Mac file systems may be different and for all I know ex Fat is too. But...

• At a low level a disk is divided into sectors which are normally 512 bytes. These are grouped into clusters which might be 512 / 1024 / 2048 bytes.
  Each cluster has an entry in the File Allocation Table, which says either "unused", "Used and the next cluster is X", or "Last cluster of the file".
• There are a limited number of entries in the FAT (2^12 originally, then 2^16 , 2^32), so you need group disk sectors together so that partition_size / cluster_size < FAT_size (since there was also a limit on the cluster size, we had to divide large disks into partitions).
• A directory entry has file name, date, attributes and the number of the first cluster.
• The root directory is (IIRC) in the first cluster(s) and has pre-allocated space (so FAT has/had a limit on the number of files in the root).
• All other directories are just "special files" - if they get too big more space gets allocated to them, their FAT entry changes from "Last block" to "Carry on at block X"
• On a FAT formatted memory card put into a camera the first file created will be the DCIM directory, so it will sit in the next cluster after the root. Generally recovering from a deleted root directory involves scanning to find things which look like they might be directories.
• If you have a directory you know how big the file is, and where to find its first block, and the FAT takes you to the others. If you don't have the FAT and the file is in contiguous sectors it's easy to put it back together, but if the disk has become fragmented you might be looking at a darn great jigsaw. [Note I've updated the original post, there are some circumstances where formatting doesn't re-write the FAT , and I can't recall how in those cases all space gets seen as "free" when it comes to be used, but there were "unformat" programs which relied on this.]
• Not withstanding the last point ... a quick format doesn't check for bad sectors. It just gets you to a position where you can use all the space again.
  By contrast as full format checks it can write to every cluster (IIRC, again, 'low level' or 'factory' formats write to each disk sector, and tell the drive to map out any bad ones. OS level formats only work at cluster level if one disk sector is bad the whole cluster is mapped out, so a full format won't necessarily erase all data, most of the time what survives isn't usable in any practical sense, but if espionage is a worry there are tools to make sure every byte is over written more than once. (And then you physically destroy the drive

Possibly someone with more up-to-date knowledge will say "yeah grandad but it now works like this", and I haven't used a low level sector editor in 25 years!

 

[Deleted member 103366]

Thank you, that's going to take several read throughs I think

 

[raulmavic]

I got it !

I used RECUVA program for scanning my Mavic Mini SD card. It found an erased folder called \101MEDIA\ inside that folder the missing files starting by DJI_0001.MP4

Thanks a lot for your help. Best regards.

R.

 

[Deleted member 103366]

I have used recuva but it was a probably a decade ago and the last time I tried to use it I couldn't get it to work. As I was pushed for time I switched to ZarX. The 'map' was a nice bonus

 

[cadbob]

Been using this tool for many many years to format sd cards etc

SD Memory Card Formatter for Windows/Mac | SD Association

www.sdcard.org

 

[Deleted member 103366]

Cadbob, when you use that do you get any 'peculiarities' with perhaps looking at or reading the card?
Some years ago I bought a 2nd hand card the had been 'dealt with' by that or something similar (the "SDA" bit seems to ring a bell) and there was something about it that unnerved me. This was, as I said, a few years ago and I don't remember the details, sorry, But, from what I do remember, I had a bit of trouble getting rid of the changes that had been made and in getting back to what I regarded as a normal card. Thanks

 

[AboriginalBrotherhood1162]

Thank-you for the update surprise warning?. I have 8 flights and total of total flight time,,,of honest real /no bs actually thumbing the gimble sticks after the 3rd full 17satellite *ok to fly*message finally popped up, my battery was already getting low,,,,,long story short...I was worried about that 1000th. flight just over my horizon. Ambition has no boundaries I guess